A pool or spa system may include various devices or systems, including, for example, automation control systems, sanitation systems, filtration systems, heaters, pumps, etc. Each device or system may include a power source or may receive power from another device. The pool system may also include a communication network bus, which may allow the various devices to provide and receive power via the communication network bus. The communication network bus may also allow the various devices to communicate (e.g., transmit or receive data). It may be desirable to monitor or control power supply between the devices via the communication network bus.